An allegedly broken promise to two oil companies and a claim for restitution of more than $150 million will soon give the U.S. Supreme Court a chance to determine just how risky it can be to have the federal government as a business partner.

The high court on March 22 will hear arguments in the combined cases of Mobil Oil Exploration & Producing Southeast Inc. v. U.S., No. 99-244, and Marathon Oil Co. v. U.S., No. 99-253. The two cases ask the justices whether the government must repay the consideration paid by a government contractor when legislation enacted after the contract was made stops the United States from performing its contractual duties.